It is known in the art that butadiene monoepoxide (EpB) and mixtures of EpB and vinyl compounds can be polymerized in a sealed system and at a temperature of 150.degree.-350.degree. C. Such a process is described in U.S. Pat. No. 2,570,601. It is stated that EpB polymerizes with itself to form a clear, yellow resin. The mixed resins are said to have low solubilities in organic solvents, particularly hydrocarbons, and are taught to be useful as surface coatings which are melted, and applied hot to the materials and articles being coated.
It is also known in the art that olefin oxides can be polymerized or copolymerized in the presence of an ionic catalyst, which comprises a dialkyl zinc and a metal oxide or hydroxide; U.S. Pat. No. 3,230,207. It is stated that the use of the metal oxide or hydroxide improves the yield of polymer, over that afforded by use of the alkyl zinc catalyst alone. The products are said to have a high degree of crystallization.
It is also known in the art that maleic anhydride can enter into various types of copolymerizations. For example, a 1:1 copolymer of allylglycidyl ether and maleic anhydride is described by N. Kaishi et al., in Kobunshi Kagaku, 24, 272 (1967). Also, it is known in the art that a cyclocopolymer can be prepared which has two maleic anhydride moieties per each divinyl ether group; G. B. Butler et al., J. Macromol Sci: Chem. A5 (1) 219 (1971).
As illustrated by the above cited art, it is known that EpB and maleic anhydride can be used individually as comonomers for polymerization with various substances. However, those references do not disclose that these two monomers can be copolymerized.
U.S. Pat. No. 3,851,015 discloses a process for producing block copolymers from monomers of different types, by polymerization in two successive steps. The first step comprises an anionic polymerization, and the second step comprises a free radical catalysis. It is stated that EpB is among the monomers which can be polymerized in the second step. The second step is conducted in the reaction mixture produced by the first step. The patent does not disclose means for copolymerizing maleic anhydride and EpB in one reaction.
Accordingly, it can be seen from the above that there is no art-recognized method for copolymerizing maleic anhydride and EpB in one step. The process of this invention provides a single step method for copolymerizing those substances; hence, it provides a significant advance over the art.